The subject matter of this application is a tire chain and a method of modifying a tire chain.
Referring to FIGS. 1 and 2 of the drawings, one known type of tire chain comprises an elongated inner side member 2 adapted to form a circle of predetermined circumference about a rim of a vehicle wheel at the inner side thereof and having cooperable fastener elements (not shown) at opposite ends thereof which are joined to complete the circle. Crosslinks 6 form a zigzag pattern including a plurality of spaced inner vertices 10 along one edge of the pattern adjacent to the inner side member and a plurality of spaced outer vertices 14 along an opposite edge of the pattern remote from the inner side member and adapted to be positioned adjacent to the rim at the outer side thereof, with the crosslinks 6 extending back and forth across the tread of a tire mounted on the rim. The inner vertices are attached to the inner side member at predetermined positions by attachment brackets 18 spaced apart along the inner side member and attached both to the inner side member and to the inner ends of the crosslinks that meet at a given vertex. The opposite, outer, end of each crosslink meets the outer end of an adjacent crosslink at an outer vertex 14 and the two outer ends, of the adjacent crosslinks respectively, are attached to an attachment bracket 18 which is attached to an elongated outer side member 22 forming part of a tensioning device for drawing the outer vertices toward the rotational axis of the wheel.
In a practical implementation of the conventional tire chain, each crosslink 6 comprises a length of flexible cable threaded through generally cylindrical traction elements and provided at each end with a crimped lug or bushing. The attachment bracket 18 comprises a metal plate that is bent in a generally C-shaped configuration and thus comprises a substantially flat part 36 intermediate two opposite curved parts. One of the two curved parts is fitted around the elongated inner or outer member 2, 22 of the tire chain and is crimped in position so as to grip the inner or outer member firmly. The other curved part of the plate is formed with two keyhole openings each having a larger, circular portion 40 and a narrower slot portion 44 extending from the circular portion 40. The circular portion of the keyhole opening is situated in the flat part of the plate and the slot portion extends partially around the curved part of the plate. The crosslink is attached to the attachment bracket by inserting the lug 32 through the circular portion 40 of the keyhole opening and then positioning the lug so that the cable 26 is located in and extends through the slot form portion 44 of the opening, whereby the lug is located interiorly of the curved part of the plate.
This type of tire chain allows replacement of the crosslinks in the event of damage, but handling of the tire chain is difficult and arduous because the crosslinks are quite heavy. Further, it has been found that in some cases the traction elements are somewhat lacking in endurance.